Torsional vibration dampers (TVDs) are used in the automotive industry to reduce vibrations in a shaft (crankshaft, drive shaft, prop shaft, etc.), thereby enhancing its fatigue life. The simplest torsional vibration damper consists of three functional components: (1) a hub, which is a rigid structural bracket that attaches the torsional vibration damper to the shaft; (2) an elastomer, which provides a spring damper system for the torsional vibration damper; and (3) an active inertial mass called the ring, which vibrates with a magnified amplitude, but exactly opposite phase relative to the shaft vibration(s). In most elastomer-based torsional vibration dampers, there are two mechanisms that actively reduce vibration: (1) by absorption of the vibrations due to tuning the torsional vibration damper to a particular frequency; and (2) by viscous damping due to the elastomeric material and the inertial system. In addition to vibration attenuation, torsional vibration dampers that are attached to the crankshaft of an internal combustion engine also power an external belt drive through an endless belt system that drives the front end accessory drive system.
There is always a need for better, less complex, less expensive, easier to manufacture, easier to assemble or disassemble torsional vibration dampers.